The teacher as well as the students who_____fond of football,_____ playing together.

A．are; is

B．are; are

C．is; are

D．is; is

你家中用电器的额定电压一般是__________V，通常情况下它们以__________的连接方式接入电路，用电饭煲煮饭是因为电流具有__________效应，如果你家中的用电器突然全部停止工作，经检查发现是空气开关掉闸了，你认为原因可能是______________（说出一种即可）。